This invention relates to processing data plots, and more particularly to processing data plots for inclusion of additional information content.
Data plots, such as scatterplots, are widely used for illustrating or finding correlations between data. Data points are positioned in a multi-dimensional space according to their values, wherein the values of a data point determine its position in the multi-dimensional space.
In order to identify data points within a data plot and provide additional information content within the data plot, labels may be used which are typically located next to a data point in the data plot. Although this labelling technique may be adequate when the number of data point is low, a data plot can quickly become visually cluttered with labels when the number of data points is increased. Thus, for a fixed available space of a 2-Dimensional plot, for example, it can be a problem to include detailed information about the data points without causing visual clutter.
Various label placement techniques are known which attempt to reduce visual clutter caused by labels in scatterplots. One such technique uses simulated annealing to avoid overlaps, whilst another uses label rotation to orientate labels at various angles in an attempt to make better use of available space. However, such known techniques fail to reduce visual clutter when the number of data points in the scatterplot is too large to display all of the required labels.
A variety of dynamic techniques are also known which require user interaction with the data plot in order to display the labels or additional information. One such dynamic approach is referred to as ‘brushing’ which only displays the label of a limited number of data points when the user selects a specific region (by hovering a cursor over the plot area for example). Although this approach reduces visual clutter, because only the label of a few selected data points is displayed at any one time, it also removes the other additional information content from the data plot.